The Wager:
I claim that, dropped from the same height, a complex, 3 dimensional structure, like multiple stories of a building, (i.e., something that is not a solid block) will generate a HIGHER peak force in the components of whatever structure on which they fall AFTER the dropped parts have been broken up & compacted than they would generate in their original, "pre-broken" state. As compacted rubble, it will also deliver a higher pressure, resulting in a higher stress and more damage in the impacted part.
Tom
OK, a complex, 3D, composite structure is dropped. Let's call it part C. It impacts whatever (!) structure. Let's assume it is same structure as C and that we call it part A. Part A carried part C before. Part C is now dropped on part A.
Then you talk about 'dropped parts have been broken up' (???) I assume you mean that part C is subject to local failures, when it impacts part A. Right?
Reason for this is that part A has applied dynamic force/energy on part C when C contacted A or A contacted C (same thing). This force damages elements in C.
Evidently this dynamic force A on C is greater than the static force that A applied on C before. But the dynamic force is of very short duration! It is a function of energy applied and distance of displacement of broken elements/connections.
Then you suggest that 'compacted rubble' exist. Let's call it part B. Sorry! No compacted rubble will develop when C impacts A. Only locally failed elements in C (and A of course) will develop, and the damaged elements will either be attached to A and C, or, in the case of C, drop off outside the structure.
The wager seems to be that part B will deliver 'a higher pressure' on part A and produce local failures in part A or a one-way crush down.
Sorry, part B does not exist and cannot be created by C and/or A at impact and can therefore not produce any forces or apply any energy on either A or C.
Suggest you look at the problem in 1D and regard parts C and A as chains of material points connected by potentials (springs). You will then realize that no new, compacted chain - part B - of material points without potentials will suddenly pop up in your model.